What is the difference between user variables and system variables?

Question

What is the difference between user variables such as PATH, TMP, etc. and system variables?

I accidentally deleted the user variable

Answer 1

Environment variable (can access anywhere/ dynamic object) is a type of variable. They are of 2 types system environment variables and user environment variables.

System variables having a predefined type and structure. That are used for system function. Values that produced by the system are stored in the system variable. They generally indicated by using capital letters Example: HOME,PATH,USER

User environment variables are the variables that determined by the user,and are represented by using small letters.